Periodontal disease occurs when bacteria colonize the sulcus space between the teeth and gingiva. The bacteria cause inflammation. The inflammation destroys the inner surface of the sulcus altering the structure from a normal epithelial cover to a surface devoid of epithelium. With the epithelial barrier destroyed, bacterial inflammation advances and destroys the periodontal attachment structures of connective tissue and bone, and stimulates a growth of granulation tissue on the inner damaged gingival surface. The inflammation then progresses down the root toward the apex of the root. As periodontal disease progresses, open pocket develop between the tooth and the gingiva. The root surface becomes contaminated with biofilm, bacterial toxins and hard adherent calcified calculus deposits.
A primary method to treat periodontal disease is to remove or debride granulation tissue and scrape the root surface clean. This procedure is done during non-surgical root planing and curettage, and surgical periodontal therapy. During root planing and curettage, operator access to the depth of the periodontal pocket is hindered since the instrument must be inserted into the limited space between the root and gingiva. In the hands of the most experienced operators, root planing and curettage cannot completely remove the hard deposits and biofilm even when utilizing both specialized hand and ultrasonic instruments as demonstrated in a recent study using fiberoptics (Perioscopy) to examine treated root surfaces. A Clinician's 3 Year Experience With Perioscopy, Dr. Roger Stambaugh, Compendium November 2002 Vol. 23, No 11A. Periodontal surgery allows a higher degree, but not complete cleaning, of root deposits. Periodontal surgery requires incisions to peel back the gingiva to allow the operator access to the root deposits.
Hand instruments are complex in design and require numerous compound shaft angles mated with a myriad of shaped scraping edges to allow the operator to clean complex curves of root surfaces in obscure positions in the mouth. have been designed number in the thousands. Ulltrasonics utilize electronics to generate a vibrating insert tip to clean the root. Ultrasonic inserts are manufactured in approximately 30–50 different sizes, designs, and angles to allow placement of the ultrasonic cleaning tip along side the roots. Hand instruments cost on average from $7.00 to $27.00 with ultrasonic inserts averaging from $80.00 to $145.00.
There is one type of powered rotary bur, the Evian Debridement Bur, designed to remove granulation tissue and root deposits. This bur cleans the root after the gingiva is incised with scalpels, loosened, and peeled away from the bone and tooth. The Evian burs have round ends varying in diameter from 1.0 mm to 1.8 mm with non-cutting grooves. Evian burs are specifically designed not to abrade the root surface. The Evian bur generally has a diameter greater than the width of the space between the tooth and gingiva and cannot easily enter the narrow periodontal pocket between the tooth and gingiva without incisions to create a wider entry space; therefore its use is limited to surgical procedures.
The objective of root planing is to remove root deposits, granulation tissue, and to detoxify the root surface of imbedded bacterial toxins. The stated goal of hand instruments, ultrasonic instruments and the Evian Bur is to remove as little of the root surface as possible. Microscopic studies reveal that these instruments achieve their goal and only gently clean the root surface leaving small scratch marks. However, root surfaces are irregular and porous. Toxic bacterial byproducts penetrate the root surface or are concealed within the irregular root surface. A disadvantage with these existing instruments is that they are specifically designed to not abrade the outer irregular root surface, and therefore they do not detoxify the root surface.
What is needed is a rotary bur designed to function without surgery, designed to enter the pocket without trauma to the tissue at the entrance of the pocket, to detoxify the root by abrading the outer surface of the root, and to debride the granulation tissue lining the periodontal pocket. I call the process of simultaneously removing the granulation tissue, removing the root deposits, and sanding off the outer root surface without the need for incisions “bur abrasion”. A further advantage is that dentin exposed by bur abrasion provides a natural source for bone morphogenic protein that speeds periodontal healing.
Some of the presently manufactured burs have a taper from a hemispherical tip to the base of the cutting head. This taper is a straight line and cannot conform to the compound curves of the root and therefore cannot adequately debride the gingiva or root.
Other common burs, such as the 1157R, are also not adequate to perform the required tasks of bur abrasion. The 1157R is a cylinder shape with its parallel sides capped by a hemisphere tip. The hemisphere tip diameter is equal to the width of the parallel sides. This blunt shape is too wide to easily enter the space between the gingiva and root without tearing the gingival tissue during placement into the periodontal pocket. To enter the periodontal pocket without trauma to the tissue requires a marked difference in design of the tip of the bur.